Control of Noise in Power Station Cooling Tower Systems

Abstract

Power-station cooling tower systems must handle large volumes of water and air with large potential energy in the water flows and the requirement for large fans. To minimize the noise generated at power station sites, use is made of efficient tower fill materials, dual low-speed fans (which shifts the spectrum and lowers mid-frequency noise level), and barrier effects in tower location and orientation. Conventional noise control measures such as mufflers are avoided because of the required increase in pressure across the fan and the high initial cost for quieting large towers. The use of natural draft towers is discussed and it is shown that although the low-frequency noise may be reduced, the noise levels at typical property line locations are of the same order of magnitude as that for conventional mechanical cooling towers. Since cooling towers at power stations are required as an environmental (thermal) pollution control measure, a trade-off between temperature rise of local water supplies versus increases in community noise becomes a critical factor.